Heating Capacity and Biocompatibility of Hybrid Nanoparticles for Magnetic Hyperthermia Treatment.

Cancer is one of the deadliest diseases worldwide and has been responsible for millions of deaths. However, developing a satisfactory smart multifunctional material combining different strategies to kill cancer cells poses a challenge. This work aims at filling this gap by developing a composite material for cancer treatment through hyperthermia and drug release. With this purpose, magnetic nanoparticles were coated with a polymer matrix consisting of poly (L-co-D,L lactic acid-co-trimethylene carbonate) and a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer. High-resolution transmission electron microscopy and selected area electron diffraction confirmed magnetite to be the only iron oxide in the sample. Cytotoxicity and heat release assays on the hybrid nanoparticles were performed here for the first time. The heat induction results indicate that these new magnetic hybrid nanoparticles are capable of increasing the temperature by more than 5 °C, the minimal temperature rise required for being effectively used in hyperthermia treatments. The biocompatibility assays conducted under different concentrations, in the presence and in the absence of an external alternating current magnetic field, did not reveal any cytotoxicity. Therefore, the overall results indicate that the investigated hybrid nanoparticles have a great potential to be used as carrier systems for cancer treatment by hyperthermia.

Thiol-antioxidants interfere with assessing silver nanoparticle cytotoxicity.

Many studies have shown that silver nanoparticles (AgNP) induce oxidative stress, and it is commonly assumed that this is the main mechanism of AgNP cytotoxicity. Most of these studies rely on antioxidants to establish this cause-and-effect relationship; nevertheless, details on how these antioxidants interact with the AgNP are often overlooked. This work aimed to investigate the molecular mechanisms underlying the use of antioxidants with AgNP nanoparticles. Thus, we studied the molecular interaction between the thiol-antioxidants (N-acetyl-L-Cysteine, L-Cysteine, and glutathione) or non-thiol-antioxidants (Trolox) with chemically and biologically synthesized AgNP. Both antioxidants could mitigate ROS production in Huh-7 hepatocarcinoma cells, but only thiol-antioxidants could prevent the cytotoxic effect, directly binding to the AgNP leading to aggregation. Our findings show that data interpretation might not be straightforward when using thiol-antioxidants to study the interactions between metallic nanoparticles and cells. This artifact exemplifies potential pitfalls that could hinder the progress of nanotechnology and the understanding of the nanotoxicity mechanism.

Grape juice concentrate alleviates epididymis and sperm damage in cadmium-intoxicated rats.

The possibility of long-term grape juice concentrate (GJC) consumption conferring a protective effect against cadmium (Cd)-induced damage to the epididymis, completely preserving sperm profile, was evaluated here for the first time in the scientific literature. Male Wistar rats (n = 6/per group) received an intraperitoneal Cd injection (1.2 mg/Kg) at age 80 days and GJC (2 g/Kg) by gavage from 50 days until 136 days old. Groups receiving either Cd or GJC were added. An intraperitoneal injection of saline (0.9%) and water by gavage was administered in the absence of treatment with Cd or GJC. Animals were anaesthetized and exsanguinated at 136 days; the vas deferens, left testis and epididymis were removed; and perfusion continued with fixative. The right epididymis was collected for morphological analysis. Cd had a devastating effect demonstrated by reduced sperm count in testes and epididymis, sperm production and normal sperm count, besides increased epididymis sperm transit time and completely disorganized morphology. These alterations were attributed to higher Cd levels in the testes and a lipid peroxidation (LP) process. Consumption of GJC plus Cd intoxication was effective, reducing metal accumulation and LP. Consequently, we could identify a preserved sperm profile, with improvement in testis and epididymis sperm count, normal sperm structure and sperm transit time. Moreover, GJC extends its protective effect to the epididymis, allowing complete re-establishment of its morphology, ensuring successful sperm maturation process. In conclusion, our study indicates long-term GJC as a promising therapy against reproductive chemical intoxication injury damage, preserving sperm prior to ejaculation.

Formulations with microencapsulated Fe-peptides improve in vitro bioaccessibility and bioavailability.

The bioaccessibility and the bioavailability of iron complexed to peptides (active) in microparticles forms contained in dry beverages formulations were evaluated. The peptide-iron complexes microparticles were obtained by spray drying and added in three dry formulations (tangerine, strawberry, and chocolate flavors). The peptides isolated by iron ion affinity (IMAC-Fe III) had their biological activity predicted by BIOPEP® database and were evaluated by molecular coupling. The bioaccessibility was evaluated by solubility and dialysability and the bioavalability was assessed by Caco-2 cellular model. The proportion 10:1 of peptide-iron complexes presented higher rates of bioaccessibility (49%) and bioavailability (56%). The microparticle with peptide-iron complex showed greater solubility after digestion (39.1%), bioaccessibility (19.8%), and bioavailability (34.8%) than the ferrous sulfate salt (control) for the three assays (10.2%; 12.9%; 9.7%, respectively). Tangerine and strawberry formulations contributed to the iron absorption according to the results of bioaccessibility (36.2%, 30.0% respectively) and bioavailability (80.5%, 84.1%, respectively). The results showed that iron peptide complexation and microencapsulation process improve the bioaccessibility and bioavailability when incorporated into formulations.

Determination of Total Silicon and SiO2 Particles Using an ICP-MS Based Analytical Platform for Toxicokinetic Studies of Synthetic Amorphous Silica.

Synthetic amorphous silica (SAS), manufactured in pyrogenic or precipitated form, is a nanomaterial with a widespread use as food additive (E 551). Oral exposure to SAS results from its use in food and dietary supplements, pharmaceuticals and toothpaste. Recent evidence suggests that oral exposure to SAS may pose health risks and highlights the need to address the toxic potential of SAS as affected by the physicochemical characteristics of the different forms of SAS. For this aim, investigating SAS toxicokinetics is of crucial importance and an analytical strategy for such an undertaking is presented. The minimization of silicon background in tissues, control of contamination (including silicon release from equipment), high-throughput sample treatment, elimination of spectral interferences affecting inductively coupled plasma mass spectrometry (ICP-MS) silicon detection, and development of analytical quality control tools are the cornerstones of this strategy. A validated method combining sample digestion with silicon determination by reaction cell ICP-MS is presented. Silica particles are converted to soluble silicon by microwave dissolution with mixtures of HNO3, H2O2 and hydrofluoric acid (HF), whereas interference-free ICP-MS detection of total silicon is achieved by ion-molecule chemistry with limits of detection (LoDs) in the range 0.2-0.5 µg Si g-1 for most tissues. Deposition of particulate SiO2 in tissues is assessed by single particle ICP-MS.

Bioavailability Assessment of Copper, Iron, Manganese, Molybdenum, Selenium, and Zinc from Selenium-Enriched Lettuce.

Cu, Fe, Mn, Mo, Selenium (Se), and Zn bioavailability from selenate- and selenite-enriched lettuce plants was studied by in vitro gastrointestinal digestion followed by an assay with Caco-2 cells. The plants were cultivated in the absence and presence of two concentrations (25 and 40 µmol/L of Se). After 28 days of cultivation, the plants were harvested, dried, and evaluated regarding the total concentration, bioaccessibility, and bioavailability of the analytes. The results showed that biofortification with selenate leads to higher Se absorption by the plant than biofortification with selenite. For the other nutrients, Mo showed high accumulation in the plants of selenate assays, and the presence of any Se species led to a reduction of the plant uptake of Cu and Fe. The accumulation of Zn and Mn was not strongly influenced by the presence of any Se species. The bioaccessibility values were approximately 71%, 10%, 52%, 84%, 71%, and 86% for Cu, Fe, Mn, Mo, Se, and Zn, respectively, and the contribution of the biofortified lettuce to the ingestion of these minerals is very small (except for Se and Mo). Due to the low concentrations of elements from digested plants, it was not possible to estimate the bioavailability for some elements, and for Mo and Zn, the values are below 6.9% and 3.4% of the total concentration, respectively. For Se, the bioavailability was greater for selenite-enriched than selenate-enriched plants (22% and 6.0%, respectively), because selenite is biotransformed by the plant to organic forms that are better assimilated by the cells.

Selenium Bioaccessibility and Speciation in Selenium-Enriched Lettuce: Investigation of the Selenocompounds Liberated after in Vitro Simulated Human Digestion Using Two-Dimensional HPLC-ICP-MS.

The evaluation of selenium-enriched vegetables as potential dietary sources of selenium, an essential element for humans, requires an assessment of the plant's accumulation ability as well as of the bioaccessibility and speciation of the accumulated selenium, which influence its biological effects in humans. Lettuce hydroponically grown at three selenite (SeVI)/selenate (SeIV) amendment levels was characterized accordingly. Selenium accumulation in lettuce leaves was greatest with Se(VI) amendment, whereas bioaccessibility was 70% on average in both cases. Selenium speciation in gastrointestinal hydrolysates, characterized by anion and cation exchange HPLC-ICP-MS, showed that Se(IV) was largely biotransformed into organoselenium metabolites, with selenomethionine accounting for 1/3 of the total detected species, whereas Se(VI) was incorporated as such in the edible portion of the plant, with only a small fraction (∼20%) converted into organic species. Taking into account both nutritional quality and safety, the Se(IV)-enriched lettuce appeared more favorable as a potential selenium source for human consumption.

Evaluation of the bioaccessible fractions of Fe, Zn, Cu and Mn in baby foods.

The bioaccessibility of four essential micronutrients (iron, zinc, copper and manganese) in some baby foods was evaluated using an in vitro gastrointestinal digestion model. For all of the flour-based foods evaluated, the bioaccessibility of Zn was low, while the bioaccessibility of Cu was above 50%. For these samples, the bioaccessibility of Mn was lower than 50%. Two samples composed of oat and rice flour and whole wheat flour demonstrated a lower bioaccessible fraction of Fe (less than 35%), while the sample made with wheat flour showed high Fe bioaccessibility (approximately 80%). For vegetable- and meat-based baby foods, the Fe bioaccessibility was greater than 80% in samples that contained meat and chicken and approximately 20% for the banana-based sample. The bioaccessibility of Zn was small for all of the foods studied, and in some cases, no Zn appeared to be released. The sample containing banana showed 100% Cu bioaccessibility, in contrast to meat and chicken-based samples, whose Cu bioaccessibility values were less than 50%. The opposite effect occurred for Mn, in which samples containing meat and chicken presented a bioaccessible fraction greater than 50% while the banana-based sample had a fraction less than 50%.